1. Field of the Invention
This invention relates to instruments for cutting, and more particularly to blades produced by microfabrication techniques.
2. Discussion of the Prior Art
Conventional blades of steel are well known. Steel blades are used in a wide variety of applications, ranging from non-precision implements such as steak knives to precision implements such as surgical instruments. Surgical blades of steel are manufactured in a variety of shapes, but all share the characteristics that sharpness and precision of the edge are important to the proper functioning of the instrument.
A electron micrograph of one such conventional steel blade is shown at a 5000.times. magnification in FIG. 1.
As seen in FIG. 1, steel blades manufactured using conventional techniques include numerous minute surface imperfections. These imperfections may result from mechanical sharpening processes or from chemical processes occurring at the surface of the blade, such as corrosion by exposure to the air. As a result, the actual cutting edge 101 of such a blade may have a significant radius, may be quite irregular (though macroscopically appearing smooth) and may vary in sharpness.
As a result of these minute imperfections, a conventional steel surgical blade cannot cut without some tearing of tissue. Such tearing of tissue during surgery may slow down healing, and also may result in scar tissue formation during and after healing is completed.
Certain delicate surgeries such as ophthalmological, cardiovascular and cosmetic procedures are rendered more difficult or yield less satisfactory results due to the problems with conventional steel surgical blades.
Finally, some processes in the manufacture of conventional steel surgical blades do not lend themselves to economical mass production of blades. For example, formation of the blade and sharpening of the cutting edge are typically separate operations. Although the blade may be formed by a precision stamping or die cutting operation, the cutting edge must be ground and honed. Each blade is individually fixtured for these operations, which may then be performed simultaneously on large numbers of blades.